Fuel injection pump



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FUEL INJECTION PUMP Filed Nov. 5, 1958 4 Sheets-Sheet 2 INVENTOR.

WALDEMATE O. BICHOFF' A T' TOPNEY Dec. 5, 1961 Filed Nov. 5, 1958` W. O. BISCHOFF FUEL INJECTION PUMP 4 sheets-sheet s INVENTOR.

WA LDC MAE O. BISCHOFF ATTOPNY.

Dec. 5, 1961 w. o. BlscHoFF FUEL INJECTION PUMP Filed Nov. 5, 1958 asf 4 Sheets-Sheet 4 F1 g' .4. F5" E'.

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WALDEMA O. BISCHOFF ATTUFNEY.

t ted States Pate 3,011,490 Patented Dec. 5, k1961 3,011,490 FUEL INJECTION PUMP Y v Waldemar O. Bischoff, Holyoke, Mass., assigner to Amer- :ican Bosch Arma Corporation, a corporation of New York v Filed Nov. 5, 1958, Ser. No.` 771,995 13 Claims. (Cl. 12S-139) This invention relates to fuel injection apparatus for Another object of the invention is to provide a new and Y improved injection timing means for fuel injection pumps, which timing means is relatively simple and economlcal Y in construction.

Another object is to provide a device of the type set forth wherein the injection timing means is embodied in the pumping and distributing member.

Another objectis to provide a new and improved fuel injection -pump of the type set forth which is relatively compact and simple in construction and assembly, yet efficient in operation.

Referring to the drawings:

FIG. l is a longitudinal sectional view of a fuel injection apparatus embodying the invention;

FIG. 2 is a sectional view taken on line 2-2 of FIG. 1, v

looking in the direction of the arrows; l

FIG. 3 is a sectional view taken on line 3;-3 of FIG` 1, looking in the direction of the arrows;

FIG. 4 is `a side View of one form of pumping andl distributing member embodying the invention;

FlG. 5 is a side view of another form thereof; FIG. 6 is a side view of another form thereof;

FIG. 7 is a side view illustrating two other possible embodiments; and

FIG. 8l is a side View illustrating another possible embodiment.

Referring more particularly tothe drawings wherein similar reference characters designate corresponding parts throughout, the apparatus shown embodying the invention comprises a housing or casing 10 in which the drive shaft or cam shaft designated generally at 11 is journalled in the bearings 12 and 13 and which drive shaft is adapted to be operatively connected to the engine and to be driven thereby.

` On the end of drive shaft 11 is mounted a spur gear 14.

The drive shaft 11 is provided with a cam 15 having the lobes 15a, the number of which depends' upon the speed at which the pump is to be driven, for example, when the drive shaft 11 is connected to a four-cycle engine and adapted to operate at one half engine speed, the number of lobes 15a on the cam is equal to the number of pump outlets and where the drive shaft 11 is adapted to be driven at engine speed, the cam is provided with one half the number of lobes 15a as the pump has outlets.

In the portion 10a of the casing or housing 10 above drive shaft 11 is provided the pump head 16 which fits into a recess 17 in said portion 10a of housing 10.

The pump head 16 has the bore 18 therethrough,` the outer end of which is closed by a threaded plug or the like 19 and the pump head 16 is provided with the out? lets 20, one of which is provided for each cylinder or combustion chamber of the engine and which outlets 20 are connected to the bore 18 by ducts or passages 21.

The pump head or hydraulic head 16 is retained in position in casing 10a by means of the ange member 22 which is secured to casing 10a by bolts or other suitable means.

The pump head 16 is provided with a peripheral recess or groove 23 adjacent the periphery of the pump head and which, together with the adjacent wall 10a of the housing, forms a sump to which fuel is supplied through pipe 24 which has an end 25 extending out of the .casing and is adapted to be connected to a suitable source of fuel such as a pipe connected to fuel 'supply pump 26, which may be of the impeller type gear or vane type, as desired or, if desired, an external fuel supply pump could be employed.

Fuel is Supplied to the bore 18 from sump 23 by means of till ports or ducts 27 which may be of suitable number, such as one port for each engine cylinder or any multiple thereof.

Intermediate the ends of bore 18 there is also provided the spill sump 28.

The plunger or pumping and distributing member 29 is positioned in bore 18 in the pump head 16 and said member 29 is provided with an axial bore 29f in the end thereof adjacent plug 19 and, at its opposite end,

' member 29 is adapted to engage 'tappet 31 and to be held in engagement therewith by spring 32which engages spring seatv 33, which spring seat engages the head on the member 29 and retains it iny engagement with tappet 31. Tappet roller 34 is provided between cam 15 and tappet 31.

Cam lobes 15a urge member 29 upward on its pumping y and distributing stroke and spring 32Yeffects the return stroke vof said member 29.

Member l29 is provided with radial fill port-s 29d, one of which is provided for each iill port 27 for supplyingk fuel fromsaid ducts 27 to the pumping chamber 18a` between'the end of member 29 and plug l19l through bore 29jc in the member 29, whereby bore 29'1 will be in communication with fill ports 27 during substantially .the complete suction stroke of member 29. Itis pointed out that only one till port 27 and radial fill port 29d are required but improved filling at higher speeds can be-obtained ywith one of said ports` 29d for each port 27. Adjacent to ports 29d, member 29 is also provided with a peripheral groove 29C which communicates with portsy ports 27 do not communicate with ports 29d. Duringthe early part of the upward or injection stroke of member 29, groove 29e 1s in communication with fill ports 27 and permits a spill back of fuel, thereby preventing thel beginning of the injection until the movement of the plunger 29 is suflicient to cause groove 29e` to pass out of communication with ports 27.

For controlling the quantity of fuel injected by the pump, a spill port 39a is provided which communicates with bore 291 in the member 2'9 and spill port 39a isv adapted to spill Ifuel from passage 29jc to spill-sump 28,

and sleeve 39 is adjustable to control or varyl the amount of spill through said-spill ports 39a to thereby control the quantity of fuel injected by the pump. Y

In the drawings the plunger 29 is.

In order that the member 29 may be rotated to align distributing port 43 with each of the outlet ducts 2,1, a face gear 44 is provided adjacent the lower end of member 29 and surrounding said member and said face gear 44 is connected to member 29 by means of pin 415 or other suitable means for operatively connecting face gear 44 with member 29.

Face gear 44 is adapted to be rotated upon rotation of drive shaft i1 and spur gear 14 through the pinion 45a which is interposed between gears I4 and 44 and in those constructions embodying a governor, as shown in FIG. l, the pinion 45 may be mounted on the governor shaft 46 for simultaneously driving the governor shaft and operating the fuel supply pump 26, as shown in the construction of FIG. l.

The governor arrangement shown is yof the type shown and described in United States Patent No. 2,518,473 and is a centrifugal type governor adapted to be 'actuated through the centrifugal force of governor weights r47 which are adapted to actuate governor sleeve 48 along governor shaft 46 and, as said governor sleeve 48 is mechanically connected to spill sleeve 39 through linkage 49, shaft 50 and eccentric 51, movement of sleeve 48 by weights 47 will effectmovement or adjustment of sleeve 39.

VThe governor weights 47 are pivotally mounted on spider 47a and three such weights are preferably provided and spider 47a is connected to governor shaft 46 by being keyed thereto such as through at engaging edges.

To provide a fuel injection pump of the type shown with means for varying the timing of injection according to pump speed, which speed is determined by the engine speed as the pump is operatively connected tothe engine and actuated thereby, a controlled groove, flat or slot may be provided connecting the top 29a of the plunger with annulus 29b as shown in FIG. 5, or between annulus 291; and annulus 29C as shown in FIG. 6 or connecting distributing slot 43 Withrannulus 29e as shown in FIG. 4.

In FIGS. 4, 5, and .6 the controlled groove, flat or slot is designated 29x. Y

If desired, instead of the groove, fiat or slot described in connection with FIGS. 4, 5 and 6, the timing could be Obtained by providing a controlled opening 29p communicating with the axial bore 29f in the plunger. This port 29p could be located in the distributing slot 43 as shown in FIG. 7 or in annulus 29b as shown in FIG. 8 and is a radial port communicating with axial bore 29j in the member 29.

A pump of the type described would take in fuel through ducts 27 to annulus 36 through axial bore 29jc to the compression chamber 118a. On compression the fuel passes through duct 29j and delivery valve 41 and passage 40 to annulus 29b on member 29 from which it passes to distributing slot 43a and out through each of the ducts 21 to the outlets respectively from which it passes to the injection nozzles.

Injection ends when the spill port 39a is uncovered by the metering sleeve 39. At that time the delivery valve seats and the action of its relief or retraction piston reduces the fuel volume in the injection line for fast nozzle closure.

Because passage 40 is in communication with groove 29b, it also communicates with timing passage 29x or port 29p and this permits leakage so that the residual pressure in the injection line can leak down towards the supply pressure which leakage takes place through port 29p or passage 29x from groove 29h to till port 27.

Because of this leakage the next pumping stroke takes correspondingly longer to replace this leaked fuel before injection pressure is reached. The amount of leakage varies with the time interval that the port 29p or passage 29x is active.

When the pump is operating at low speed, leakage time is greater than when the pump is operating at high speed and, therefore, at low pump speeds greater leakage will occur causing a greater delay in the beginning of injection and conversely an advance in timing or beginning of injection will occur with increase in pump speed.

When the fuel injection pump embodies the timing feature as set forth above, the action of the retraction piston of the delivery valve is increased by the amount of fuel leakage through port 29x or passage 29p so that the residual line pressures in the fuel delivery lines can leak down towards the supply pressure. The actual amount of leakage will vary with the speed of the pump, being less for higher speeds.

On the succeeding pumping stroke the amount of the leakage plus the amount of the delivery valve retraction volume have to be made up before there is any actual fuel delivery to the nozzle and, if this amount of fuel to be made up is made to vary with speed, becoming less with higher speeds, then the beginning of actual injection will vary also with speed and this beginning of injection will be earlier or advanced with the higher speeds.

During ,the operation of the fuel injection pump, the groove, flat or slot 29x or the port 29p forms the leakage path and any fuel leaking therethrough has to be made up on the neXt pumping stroke of the member 29 and the actual amount of fuel leaking back through said ports 29d or grooves 29x will vary with the speed of the pump,

lbeing less for higher speeds and this leakage amount will have to be made up before there is any actual fuel delivery to the nozzle and, as this leakage will vary with speed, then the beginning of actual injection will also vary with speed and thus the beginning of injection will be earlier or advanced with the higher speeds, thus providing automatic advance in timing of injection for such higher speeds.

The idle control is provided by spring 65 which is connected to idle adjusting screw `66 which is adapted to adjust the position of spring 65 relative to governor lever 67.

Full load adjusting screw 68 is provided for controlling the desired full load fuel quantity and is provided with torque control screw 69 which is resiliently urged into full load position by spring 70, which allows torque control screw 69 to move slightly beyond full load position for providing the desired torque backup. The screw 68 is screwed into place to retain the unit in full load fuel position and then the torque control screw .69 is adjusted to desired position.

From the foregoing it will be seen that I have provided new and improved means for obtaining all of the objects and advantages of the invention.

I claim:

1. In a device of the character described, a `housing having a bore, a pumping and distributing member in said bore, a plurality of outlets communicating with said bore, fuel supply passage means for supplying fuel to said bore, means for effecting reciprocation and rotation of said pumping fuel and distributing member for pumping and distributing fuel to each of said outlets successively and fuel passage means for allowing leakage from said outlets back to an area which is under supply pressure during the filling portion of the stroke of said pumping and distributing member.

2. In a device of the character described, a housing having a bore, a pumping and distributing member in said bore, a plurality of outlets communicating with said bore, fuel supply passage means for supplying fuel to said bore, means for effecting reciprocation and rotation of said pumping fuel and distributing member for pumping and distributing fuel to each of said outlets successively and fuel passage means for allowing leakage from said outlets back to an area which is under supply pressure during the filling portion of the stroke of said pumping and distributing member, and a delivery valve in the fuel path ybetween the pumping and distributing portions of said pumping and distributing member.

3. In a device of the character described, a housing having a bore, a. pumping and distributing member in said bore, a plurality of outlets communicating with said bore, fuel supply passage means for supplying fuel to said bore, means for effecting reciprocation and rotation of said pumping fuel and distributing member for pumping and distributing fuel to each of said outlets successively and fuel passage means for allowing leakage from said outlets back to an area which -is under supply pressure during the filling portion of the stroke of said pumping and distributing member, and a delivery valve in the fuel path between the pumping and distributing portions of said pumping and distributing member, said leakage bypassing said delivery valve.

4. In a device of the character described, a housing having a bore, a pumping and distributing member in said bore, a plurality of outlets communicating with said bore, fuel supply passage means for supplying fuel to said bore, means for effecting reciprocation and rotation of said pumping fuel and distributing member for pumping and distributing fuel to each of said outlets successively and fuel passage means for allowing leakage from said outlets back to an area which is under supply pressure during the lling portion of the stroke of said pumping and distributing member, said leakage being of a predetermined amount.

5. In a device of the `character described, a housing having a bore, a pumping and distributing member in said bore, a plurality of outlets communicating with said bore, fuel supply passage means for supplying fuel to said bore, means for effecting reciprocation and rotation of said pumping fuel and distributing member for pumping and distributing yfuel to each of said outlets successively and fuel passage means for allowing leakage from said outlets back to an area which is under supply pressure during the filling portion of the stroke of said pumping and distributing member, and a delivery valve in the fuel path between the pumping and distributing portions of said pumping and distributing member, said leakage being of a predetermined amount.

6. In a device of the character described, a housing having a bore, a pumping and distributing member in said bore, a plurality of outlets communicating with said bore, fuel supply passage means for supplying fuel to said bore, means for effecting reciprocation and rotation of said pumping fuel and distributing member for pumping and distributing fuel to each of Said outlets successively and fuel passage means for allowing leakage from said outlets back to an area which is under supply pressure during the filling portion of the stroke of Said pumping and distributing member, and a delivery valve in the fuel path between the pumping and distributing portions of said pumping and distributing member, said leakage bypassing said delivery valve and being of a predetermined amount.

7. In a device of the character described, a housing having a bore, a pumping and distributing member in said bore, a plurality of outlets communicating with said bore, fuel supply passage means for supplying fuel to said bore, means for effecting reciprocation and rotation of said pumping fuel and distributing member for pumping and distributing fuel to each of said outlets successively and fuel passage means for allowing leakage from said outlets back to an area which is under supply pressure during the filling portion of the stroke of said pumping and distributing member, said fuel passage means being formed on the periphery of said pumping and distributing member.

8. In a device of the character described, a housing having a bore, a pumping and distributing member in said bore, a plurality of outlets communicating with said bore, fuel supply passage means for supplying fuel to said bore, means for effecting reciprocation and rotation of said pumping fuel and distributing member for pumping and distributing fuel to each of said outlets successively and fuel passage means for allowing leakage from said outlets back to an area which is under supply pressure during the filling portion of the stroke of said pumping and distributing member, said fuel passage means being formed on the periphery of said pumping and distributing member and connecting the distributing and filling portions of said pumping and distributing member.

9. In a device of the character described, a housing having a bore, a plurality of outlets communicating with said bore, passage means for supplying fuel to said bore, a pumping and distributing member mounted for reciprocation and rotation in said ybore for pumping and distributing fuel to said outlets, said pumping and distributingmember having an annulus in its periphery adapted to communicate with said supply passage means and a second annulus in its periphery adapted to receive fuel pumped by said pumping and distributing member and supply such fuel to the distributing portion thereof, and fuel passage means connecting said fill annulus with said delivery annulus for allowing leakage of fuel from said outlets back to an area which is opened to supply pressure during the filling portion of the stroke of the pumping and distributing member.

l0. In a device of the character described, a housing having a bore, a plurality of outlets communicating with said bore, passage means for supplying fuel to said bore, a pumping and distributing member mounted for reciprocation and rotation in said bore for pumping and distributing fuel to said outlets, said pumping and distributing member having an annulus in its periphery adapted to communicate with said supply passage means and a second annulus in its periphery adapted to receive fuel pumped by said pumping and distributing member and supply such fuel to the distributing portion thereof, and fuel passage means connecting the distributing portion of said member with said fill annulus for allowing leakage of fuel from said outlets back to an area which is 'opened to supply pressure during the filling portion of the stroke of the pumping and distributing member.

11. In a device of the character described, a housing hav-ing a bore, a plurality of outlets communicating with said bore, passage means for supplying fuel to said bore, a pumping and distributing member mounted for reciprocation and rotation in said bore for pumping and distributing fuel to said outlets, said pumping and distributing member having an annulus in its periphery adapted to communicate with said supply passage means and a second annulus in its periphery adapted to receive fuel pumped by said pumping and distributing member and supply such fuel to the distributing portion thereof, and fuel passage means connecting said outlet annulus with the adjacent end of said pumping and distributingv member whereby fuel may pass from said outlet annulus to the pumping chamber of said pump for allowing leakage of fuel from said outlets back to an area which is opened to supply pressure during the filling portion of the stroke of the pumping and distributing member.

12. In a device of the character described, a housing having a bore, a plurality of outlets communicating with said bore, passage means for supplying fuel to said bore, a pumping and distributing member mounted for reciprocation and rotation in said bore for pumping and distributing fuel to said outlets, said pumping and distributing member having an annulus in its periphery adapted to communicate with said supply passage means and a second annulus in its periphery adapted to receive fuel pumped by said pumping and distributing member and supply such fuel to the distributing portion thereof, said pumping and distributing member having an Laxial bore and a port connecting said axial bore with said distributing portion of said member for allowing leakage of fuel from said outlets back to an area which is opened to supply pressure during the filling portion of the stroke of the pumping and distributing member.

13. In a device of the character described, a housing having a bore, a plurality of outlets communicating with said bore, passage means for supplying fuel to said bore, a pumping and distributing member mounted for reciprocation and rotation in said bore for pumping and distributing fuel to said outlets, said pumping and distribut- 7 ing member having an annulus in its periphery adapted to communicate with said supply passage means and a second annulus in its periphery adapted to receive fuel back to an area which is opened to supply pressure during the filling portion of the stroke of the pumping and 10 distributing member.

8 ReferencesCited in the le of this patent UNITED STATES PATENTS 

